Stereographic three dimensional (3D) display systems create the illusion of depth by displaying different flat images to each of viewers' left and right eyes. Some 3D display systems alternately display left eye and right eye images (e.g., by alternate-frame sequencing) on the same display. Shutter glasses worn by viewers are synchronized with the display to pass light to each eye only during the interval in which the corresponding image is displayed.
In order that each eye sees only the image intended for it, shutter glasses must be synchronized with the images displayed. If shutter glasses are out of synchronization with the display, undesirable visual artifacts (e.g., a horizontal band of blurriness, often at the top of the display) may result. Shutter glasses may be out of synchronization with the display due to variations in display panels, fabrication of shutter glasses, or operating conditions, among other reasons.
Accordingly, there is need for methods and apparatus providing improved synchronization of shutter glasses with the display of such images.